Forms for the production of precast concrete slabs have traditionally made of wood, and while the wooden forms have the advantage that they can be cut and nailed to a desired form size, they have the known disadvantage of requiring considerable time, labor and expense in the assembling and lining for each dimensional job and also in the dismantling after the concrete has properly set. Further, the constant cutting, nailing and re-nailing limits the number of times the forms can be re-used.
Forms made of other materials, such as steel, aluminum or other metals, have also been used. However, whereas the metal is more durable than the wood, the disadvantage is that the inability to cut the forms to size requires maintaining a large inventory of forms of varying size, or in the alternative developing telescoping and locking arrangements requiring multiple section sizes and movable parts for locking and anchoring. Efforts to avoid the use of wooden forms are disclosed for example in U.S. Pat. Nos. 2,722,045; 3,495,800; and 4,121,804.
It is an object of the present invention to provide an adjustable form which substantially overcomes the several problems referred to above in connection with prior wooden and metal forms.
It is another object of the invention to provide forms which may be adjusted to varying sizes but which are assembled from components all of which have identical size and configuration, so that stockpiling of multiple form components is unnecessary.
It is a further object of the invention to provide forms which are versatile in the production of concrete slabs or other construction materials of varying sizes, patterns and colors, and with varying edge-interlocking configurations.
It is a still further object to provide forms which are simple to assemble and disassemble, which are durable and can be reused indefinitely, and which avoid the wastage and inefficiency of the prior art forms.
Other objects and advantages will become apparent as the specification proceeds.